Adaptive differential protection for transformers in grid-connected wind farms

Abstract

Summary In response to energy requirements and environmental concerns, renewable energy technologies including wind power are considered to be the potential alternatives. Generally, wind farms are integrated into the grid through a transformer, and its rating depends upon the capacity of wind farms. The fault current of the system to which wind farm is connected changes according to the wind generators in service as well as with the wind speed. The study shows that the existing differential relay for transformer protection mal‐operates during fault interval according to the operating conditions of the wind farm. Under such conditions, the generalized characteristics for the differential relay of the transformer need modification. The protection scheme should be capable of functioning satisfactorily under various dynamic conditions of the wind, which can be achieved through adaptive relaying. In this work, an algorithm for transformer differential protection according to the variation in wind power injection is proposed. A case study of a typical wind farm shows that the proposed algorithm adaptively modifies the settings of the differential relay with varying wind farm currents, according to the wind generators in service, as well as with regard to different wind speed conditions. The modified algorithm is also validated using the experimental setup in the laboratory.

Development of an adaptive differential protection scheme for transformer during current transformer saturation and over‐fluxing condition

“…This is because the threshold set in the above schemes may be breached during the over-fluxing condition, thus failing to prevent the issuance of the trip signal during such condition. Adaptive techniques, 17,18,19,20 nowadays have become very popular in power transformer protection. Most of the cases are concerned with the shifting of biased differential characteristics to avoid maloperation during CT saturation conditions in the adaptive mode.…”

Dynamic social privacy protection based on graph mode partition in complex social network

“…Despite the notable achievements that have been made, research in this area is still in its infancy [6]. In noninteractive privacy-preserving social network analysis, current efforts have been focused on one-time instead of serial releases of social network data [7]. On the one hand, this amplifies the inherent uncertainty of the existing deanonymization methods, and on the other hand, it makes it very difficult to carry out dynamic analysis over the anonymized data [8].…”